Effect of actinomycin D on the ability of IL-10 to upregulate TNF-RII mRNA levels in LPS-stimulated monocytes. Monocytes (5 × 10⁶ cells/mL) were preincubated for 30 minutes at 37°C with medium alone or rhIL-10 (10 ng/mL) in the presence or absence of actinomycin D (5 μg/mL), and then stimulated with LPS (100 ng/mL) for an additional 3 hours. At the end of the incubation period, cells were harvested, RNA isolated, and levels of TNF-RII mRNA determined by Northern blotting.